Dynamo-electric machine.



U. P. STEINMETZ. DYNAMO ELECTRIC MACHINE.

APPLICATION FILED MAR.20, 1909.

940,210. Patented Nov. 16,1909

WITNESSES; .HYYEAZTUE V0... M UHAHLEE 2-7 ETE'IM/I/IETZ H W gm Mam Toall whom it may concern:

' UNITED STATES PATENT orator;

CHARLES P. STEINMETZ, OF SCHENECTA'DY, NEW YORK, ASSIGNOR TO GENERALELECTRIC COMPANY, A CORPORATION NEW YORK.

DYNAMO-ELECTERIC MACHINE.

Be it known that I, CHARLES P. Swain- METZ, a citizen of the UnitedStates, residing at Schenectady, county of Schenectady, State of NewYork, have invented certain new and useful Improvements in Dynamo-Electric Machines, of which the following is a specification.

My invention relates to dynamo-electric machines, and its object is toprovide a novel and simple means for improving commutation in certaintypes of machines.

It is well known in the art that commutation may be improved in either adirect-current motor or generator by means of commutating poles providedwith windings adapted to produce a proper magnetization of thecommutating poles. It is further well known that the magnetization ofthe commutating poles must be in the opposite direction to that whichwould be produced by the armature reaction in either generator or motor,

that is, if the commutating pole were un- Wound, the'magnetizationproduced in the pole in either a generator or motor would be such as toailect commutation injuriously. I have discovered, however, that incertain classes of machines an armature reaction exists which can beutilized for producing the proper magnetization of a comniutating poleso as to improve commutation.

In the ordinary rotary converter the ar- 1 mature ampere turns due tothe alternating motor current supplied through the collector rings areapproximately equal to the ampere turns of the direct generator currentdelivered from the commutator, so that armature reaction is almostwholly absent. If, however, the armature of a rotary converter is causedto deliver mechanical power, the magnetizing effects of motor andgenerator currents are no longer balanced; but the motor current is inexcess. Since the arnuu ture reaction due to the generator current alonewould be in a direction to produce a flux injurious to commutation, itfollows that the armature reaction due to the motor current which is inthe opposite direction will produce a fiux in the proper directionSpeeifioation'of Letters Patent. Patented Nov. 16,1909. Applicationfiled. March 20, 1909. Serial No. 184,6873

v for improving the commutationof the generator current, and since inthecaseof a ro tary converter delivering mechanical power mutation ofthe machine can be improved by placing unwound commutating polesat thepoints of commutation of the generator our the motor armature reactionis in excess or the generator armature reaction, the comrent;wliichpoles are magnetized by the resultant armature reaction, or inother words, by that portion of the armature re action due to the motorcurrent which is in excess of the armature reaction due to the directcurrent. a

. My invention, accordingly, consists of a i dynamo-electric mach inehaving an arma-Y ture provided with a commutator, electrical connectionswhereby motor current is de-' livered to, and generator current takenfrom, said armature, one vof the currents flowing through the commutatorand being less in amount than the other of said currents, and unwoundcommutating poles located at the points of commutation of the currentsflowing through the commutator and magnetized by the resultant armaturereaction. 1 Y

My invention will best be understood by reference to the accompanyingdrawings, in which- Y Figure 1 shows diagrammatically a rotary converterarranged in accordance wittrmy invention; and Fig. 2 shows aself-exciting synchronous motor similarly arranged' In Fig. 1, Arepresents the armature, which is provided with a commutator B andcommutatorbrushes b b. 'C represents collector rings connected toalternating current leads D. E represents direct-current leads connectedto the commutator brushes 6 b. F represents the field magnet having mainpoles on which are the field coils f f, and f f represent unwoundcommutating poles located at the points of commutation of the,currentflowing through the co1nmu- 40 exciting synchronous motor.

current is being delivered to the armature through the leads D andcollector ring C, while direct-current is being taken from thecommutator brushes I) b through leads E and mechanical power is beingdelivered from the armature through belt G, the armature ampere turnsdue to the alternating motor current will be in excess of the ampereturns due to the direct generator current by an amount depending on theamount of mechanical power delivered through the belt G. There will,therefore, be a resultant armature reaction, which, as heretoforeexplained, is in a direction for producing a magnetization of the commutat'ing poles f, which will assist the commutation of the direct currentdelivered by the machine. Similarly, it direct current is being suppliedto the machine through the leads E andcommutator B, and alternatingcurrent is being delivered by the machine through the collector rings (Jand leads D while mechanical power is being delivered tothe armaturethrough the belt'G, the ampere turns due to the alternating generatorcurrent will be in excess of the ampere turns due to the direct motorcurrent, and,

since, as in any direct current motor, themotor current flowing throughthe commutator tends to magnetize the commutating poles in the wrongdirection, the alternating generator current, the magnetizing eilifeetof which is opposed to that of the direct motor current, produces amagnetization of the commutating poles in the proper direction forimproving the commutation of the direct motor current delivered to themachine.

Fig. 2 represents diagrammatically a self- The arrangement is the sameas that of Fig. 1, except that the direct current generated anddelivered through the commutator is supplied only to the field coils f,and not to any external circuit. The conditions in this machine areprecisely the same as those first mentioned in the discussion of Fig. l,that is, the alternating motor current being in excess of the directgenerator current, produces a magnetization of the commutating poles inthe proper direction for improving the commutation of the currentdelivered through the commutator. While I have illustrated only twoapplications of my invention, it will be understood that it isapplicable as has been said before, to any machine in which motorcurrent is delivered to and generator current taken from the armature;one of the currents How- *ing through the commutator and being less inamount than the other current. Consequently, I do not desire to limitmyself to the particular construction and connections Shown, but aim inthe appended claims to cover all modifications which are within thescope of my invention.

What I claim as new and desire to secure by Letters Patent ot' theUnited States, is, Y 1. r dynamo-electric machine having an armatureprovided with a commutator, electrical connections whereby motor current is delivered to, and generator current taken from, said armature,one of the currents flowing through the commutator and being less inamount than the other of said currents, and unwound commutating poleslocated at the points of commutation of the currents flowing through thecommutator and magnetized by the resultant armature reaction.

2. A dynamo-electric machine having an armature provided with acommutator, electrical connections whereby motor current is delivered toand generator current taken from the armature, the generator currentbeing taken through the commutator and the motor ampere turns in thearmature being in excess of the generator ampere turns, and unwoundcommutatingpoles located at the points of commutation of the generatorcurrent and magnetized by the resultant armature reaction.

3. A dynamo-electric machine having an armature provided with acommutator, electrical connections whereby motor current is delivered toand generator current taken from the armature, the generator currentbeing taken through the commutator, me-

chanical connections whereby mechanicalv power is delivered by thearmature, and unwound commutating poles located at the points ofcommutation of the generator current and magnetized by the resultantarmature reaction.

4. A. dynamo-electric machine having an armature provided with acommutator, electrical connections whereby motor current is deliveredto' and generator current taken from the armature, the generator currentbe ing taken through the commutator, and un- Wound eommutating poleslocated at the points of commutation of the generated cur rent andmagnetized by the resultant armature reaction.

5. A dynamo-electric machine having an arn'iature provided with acommutator and collector rings, electrical connections to saidcommutator and collector rings whereby motor current is delivered to andgenerator current taken from the armature, the armature. ampere turnsdue to the current through the collector rings being in excess of theampere turns due to the current through the commutator, and unwoundcommutating poles located at the points of commutation of the currentflowing through the commutator.

6. A dynamo-electric machine having an armature provided with acommutator, election of the current flowing through the com- 10 tricalconnections whereby motor current is mutator. v

5 delivered to and generator current taken It Witness whereof, I havehereunto set from the armature, one of said currents any hand this 15thday of March, 1909.

flowing through the commutator, mechan- T v 10211 connections wherebymechanical power CHARLES STEIB MErlL is transferred between the armatureand WVitnesses:

another machine, and. unwound comlnutat- JOSEPH L. R. HAYDEN,

inn ooles located at the points of commutw T. N. NooNAN.

